ITU-T Rec. G.957 (1990) – OPTICAL INTERFACES FOR EQUIPMENTS AND SYSTEMS RELATING TO THE SYNCHRONOUS DIGITAL HIERARCHY
FOREWORD
1 Introduction
    1.1 Abbreviations
2 Classification of optical interfaces
3 Parameter definitions
    3.1 System operating wavelength range
    3.2 Transmitter
        3.2.1 Nominal source type
        3.2.2 Spectral width
        3.2.3 Mean launched power
        3.2.4 Extinction ratio
        3.2.5 Eye pattern mask
    3.3 Optical path
        3.3.1 Attenuation
        3.3.2 Dispersion
        3.3.3 Reflections
    3.4 Receiver
        3.4.1 Receiver sensitivity
        3.4.2 Receiver overload
        3.4.3 Receiver reflectance
        3.4.4 Optical path power penalty
4 Optical parameter values for SDH applications
5 Optical engineering approach
    5.1 Design assumptions
    5.2 Worst-case design approach
    5.3 Statistical design approach
    5.4 Upgradability considerations
ANNEX A – System operating wavelength considerations
A.1. Operating wavelength ranges determined by fibre attenuation
A.2 Operating wavelength ranges determined by fibre dispersion
APPENDIX I – Measurement of the mask of the eye diagram of the optical transmit signal
I.1 Measurement set-up
I.2 Transfer function of the optical reference receiver
APPENDIX II – Methods for measuring reflections
II.1 Optical continuous-wave reflectometer
II.2 Optical time-domain reflectometer
APPENDIX III – Possible method for evaluating aging margin contribution in receiver sensitivity specifications
III.1 Receiver sensitivity and eye opening
III.2 S/X test method
APPENDIX IV – Upgradability examples
Reference